1 Ganglia-groups of neuron cell bodies that lie peripheral to the central nervous system in vertebrates. 2  Bipolar neurons-cell body located near the middle of the axon; characteristic of retinal neurons. 3  Unipolar neurons-cell body lies off to one side of axon; characteristic of sensory neurons.
The principal host for diamonds are rocks formed in the earth's mantle that are known as eclogite and peridotite that are carried to the earth's surface in magmas known as kimberlit e and lamproite.
Examples of gemstones formed in igneous rocks include tourmaline, aquamarine, topaz, kunzite, and feldspars like sunstone and amazonite. Many other gemstones can be found within igneous rock formations but they are not a direct result of the formation of igneous rocks. They are called secondary deposits because they form after the primary deposit.